In clothes dryers it is usual practice to mount a number of temperature sensitive devices, such as thermostats, in strategic places in the air flow path to constantly monitor the temperature of the air stream at each strategic location to control the amount of electric energy used by heating elements in the electric dryer or gas used by a burner in a gas dryer.
Typically, there are two varieties of thermostat designs which are used in dryers and other appliances. One type of thermostat is referred to as the air stream type where the sensing bulb of the thermostat includes a reacting disc provided on a leading surface of the bulb that protrudes about 9 mm inside the surface on which the thermostat is mounted. Another typical thermostat is a surface mount type wherein the bulb sits outside the surface on which it is mounted and the reacting disc flush against to the surface which it is sensing. Both these types of thermostats are usually mounted by means of screws. However, the problem with using screws is that the screws require assembly. Further, when the screws are tightened they sometimes push the legs of the thermostat out of position lifting the reacting disc face away from the surface. Consequently, this effects operation of the thermostat. Further, for the purposes of servicing, having to remove the screws may be a difficult task.
The difficulty with the air stream type of thermostat is that in certain applications it protrudes a relatively large distance into the air stream and requires a high temperature setting level. Accordingly, it would be beneficial to develop a generally flush mounted thermostat with the reacting disc of the bulb type thermostat protruding a small distance such as about 2 mm, for example, into the air stream. It would be further advantageous to provide a thermostat which may be mounted to a mounting surface without the use of screws and can be easily removed for servicing.
Two thermostat mountings which have been developed in the past without the use of screws are shown in U.S. Pat. No. 4,297,668 issued Oct. 28, 1981 to Donald E. Place and U.S. Pat. No. 4,649,712 issued Mar. 17, 1987 to Ralph Tate, Jr. et al. U.S. Pat. No. 4,297,668 teaches the use of a bracket having a pair of legs which surround a tubular type member and a second pair of legs which grasp the sides of the thermostat such that the reacting disc of the thermostat is placed in contact with a surface of the bracket which lies against the tubular structure. U.S. Pat. No. 4,649,712 shows the mounting of a bulb type thermostat in the recess of a ice making appliance. The thermostat is mounted in interference fit with the recess by the use of a pair of spring clips having a serpentine cross-sectional shape. The arrangement allows for the reacting disc of the thermostat to protrude slightly into the air stream. The problem associated with this device is that the interference fit would appear to make it difficult to remove the thermostat from the recess.